The role of regulatory T cells in the modulation of anti-tumor immune response

Abstract

Regulatory T cells (T reg) represent a subset of CD4 + T{cyrillic} cells whose function is to suppress immune responses. T reg lymphocytes can be divided into two subsets: natural nT reg lymphocytes that are developed in the thymus and inducible iT reg lymphocytes, which originate from conventional T lymphocytes on the periphery. The majority of T reg lymphocytes express high levels of interleukin-2 (IL-2) receptor α chain (CD25) and transcription factor FoxP3 (critical for the development and suppressor activity of iT reg lymphocytes). Cancer cells can modulate anti-tumor immune response indirectly, through the activation of T reg lymphocytes. It has been shown that the loss of regulatory function by depletion of tumor-induced T reg lymphocytes may enhance effectors response, resulting in tumor rejection, while the increased number of Treg lymphocytes effectively prevents tumor destruction. nT reg lymphocytes express increasingly CTLA-4 and membranebound TGF-β, which inhibits cytokine production and responses of effectors lymphocytes. iT reg lymphocytes secrete immunosuppressive cytokines such as IL-10 and TGF-β. T reg lymphocytes represent one of important obstruction in anti-tumor immunity.